Accessibility links

Genetically Engineered Goats: Technology Faces Challenges on Many Fronts


At a small biotechnology company outside Montreal, Canada, the future looks like milk from a goat -- a genetically engineered goat that's engendered both controversy and millions of dollars in funding from both the U.S. and Canadian governments.

Not many scientists operate goat farms as part of their work, but Canadian Jeffrey Turner is no ordinary scientist, and contrary to appearances, these are not ordinary goats.

"When one takes a look at a genetically-modified animal, a transgenic animal, you really see no difference," noted the scientist. "A goat is a goat."

Except, that is, when a goat is part spider. "What we've done is added one more, highly-characterized gene to these animals when they were just a single cell," explains Dr. Turner.

At his company, Nexia, a few kilometers from the bio-secure goat farm outside Montreal, Dr. Turner presides over tanks full of frozen goat semen and ova -- and milky-smelling laboratories. He's a molecular biologist and genetic engineer who's created goats that have just one spider gene, or even one human gene, added to the 70,000 genes that make a goat a goat:

"That particular gene can be shown here in a background of chromosomes," he explains. "The goat DNA is stained in orange. And the single gene that's added to this is shown in yellow."

Why tinker with goats? The answer is simple: Goats produce a lot of milk. "All our products come from milk," he said, "be it spider silk or countermeasures for terrorism."

"Spider goats," for example, produce an extra protein in their milk that can be spun into manmade spider silk. Spider silk is stronger, by weight, than anything else on earth.

The hope was to spin silk from milk and use the ultra-light material for things like bulletproof vests. But it turns out that it takes a lot of goat milk to make just a small bit of silk. Dr. Turner says, “The challenge is simply really to produce it on a cost effective basis. Unlike bulk polymers that can be produced for a few dollars or a hundred dollars per kilogram, this material is more expensive, in the $1,000 range."

So, for now the idea of making bulletproof vests out of spider silk has been put aside, though the company is pursuing some other uses of the material -- medical sutures, for example.

But Nexia has a more urgent project, one that may be more controversial. Recently, the U.S. Army asked Dr. Turner if he could engineer goats with a single human gene -- the gene that produces an enzyme called butyryl cholinesterase, or BChE.

BChE is present in small quantities in all human blood, where it acts to protect against natural poisons. If injected in far larger amounts, in the goat milk form that Dr. Turner calls "Protexia," it may protect the body from chemical weapons such as VX and Sarin gas, the agent used in the 1995 Tokyo subway attacks.

"In the absence of Protexia, if you were in a room with multiple lethal doses, you would die very, very quickly, in minutes," said Dr. Turner. "In the presence of Protexia, we expect you wouldn't even realize there was nerve agent in the air."

But critics of Nexia say that, like spider silk bulletproof vests, Protexia is far from a sure thing.

Genetic engineering opponent Andrew Kimbrell says putting genes from one species into another is both dangerous and unethical. "The fact of the matter is the technology that Nexia is doing and many of its partner companies does not and has not worked," he said.

"This company has not made one single dollar on a product they've actually sold," continued Mr. Kimbrell. "They've only made money on people giving them money for research."

About genetic engineering's mixing of genes from very different organisms, he says,"This has never happened before in the history of nature. Other companies are taking firefly genes and putting them into tobacco plants, they're taking human genes and putting them into salmon, they're taking flounder genes and putting them into tomatoes. We've never seen this before. Thank goodness we've never had any natural mating between humans and mice, or flounders and tomatoes. This is something completely new. It's crossing species boundaries at will."

Dr. Turner mentions that saving lives is what's most important. Soldiers and police could be treated preventively, he says, and Protexia would also work as an antidote, if given soon after an attack. Holding up a small vial of milk he said, "So basically what you have here in this much milk, you'd be able to get two or three doses. And if that was injected into your body, it makes you immune from the toxic effects of nerve agents. The question now is, how do we get more of this type of milk? And the answer is, more goats."

Nexia plans to grow to 1,000 goats, enough to produce about five million doses of Protexia a year. Dr. Turner says the transgenic goats will never breed outside the herd.

Yet Andrew Kimbrell says that accidents will happen, especially because biotech is largely unregulated. "The environmental implications of getting these genes out there in these species, have never really been looked into," he says. "The safety of these products from these unnatural mixes has never been looked into. Our own FDA doesn't even have rules on genetically engineered animals yet. At a minimum, we should have a public debate before millions and billions of our taxpayer dollars are given to create these transgenic chimeras."

Nexia is developing Protexia under about $5.5 million in grants from the U.S. and Canadian military.

XS
SM
MD
LG